Not that I'm aware of. SLI just means two 680M chips in one and you would have to have a laptop that would accept that upgrade which I'm not sure there are any. Not to mention how expensive it would be.
no. you cant even build your own laptop. not to mention mobile graphics are not to be sold other than to the OEMs. and if you are getting a high end laptop, you are way better off with a proper desktop
CLEVO is a large Taiwanese computer company specializing in laptops. While the Clevo brand name is perhaps not widely known, their products are re-branded and sold by known boutique brand OEMs (Original Equipment Manufacturers)… notably Sager, VoodooPC, Falcon Northwest, Eurocom, etc. They are also considered (by whoever knows about notebooks) to design and manufacturer the best of the best notebooks in terms of superior build quality and innovative designs.
The Clevo 370EM for example comes with the following GFX choices:
AMD® Radeon™ HD 7970M 2GB GDDR5 - ETA April 29, 2013 $0.00
Dual NVIDIA® GeForce™ GTX 670MX's Total 6GB GDDR5 in SLI $150.00
NVIDIA® GeForce™ GTX 680M 4GB GDDR5 Memory $200.00
Dual AMD® Radeon™ HD 7970M's total 4GB GDDR5 in CrossFireX™ - ETA April 29, 2013 $350.00
Dual NVIDIA® GeForce™ GTX 680M's total 8GB GDDR5 in SLI! $850.00
NVIDIA® Quadro™ K5000M Graphics with 4GB GDDR5 Video Memory $1,800.00
If you had one with the single 680M and wanted to upgrade, it could certainly be done.... whether you could find someone willing to sell you the parts is another story. I have had my GPU upgraded in a Clevo laptop tho it was done during a warranty replacement, I just paid for the difference in cost between the one that died and the newer one.
I think everyone is getting way ahead of themselves. The OP didn't say anything about wanting a new system. He wanted to buy a 680m SLI for his current system, probably after seeing some benchmarks and thinking it was just a matter of putting a new card in.
Also, it's at least the second time he's made this thread.